1. Field of Invention
The invention relates to on-site construction of concrete barriers for roadways. More specifically, the invention relates to the construction of concrete barriers with a steel reinforced frame using collapsable separating members or "cores," which, when collapsed, can be easily removed from the barrier. By removing the "cores," spaces are left in the otherwise continuous barrier of the size and shape of the "cores," which allow for water to properly drain and for the concrete to expand or contract without breaking during changing atmospheric conditions.
2. History and Prior Art
When building or repairing roads or bridges, it is desirable to have concrete barriers in certain places on the roadside to prevent cars from leaving the right-of-way. This is particularly true where the barriers protect bridges or curving right-of-ways or where the barriers are set up to protect workers on a road or bridge just off the right-of-way. Concrete barriers are also used to separate traffic lanes.
It is necessary that such barriers be constructed of sufficient strength to withstand the impact of a swerving vehicle. It is also necessary that the barriers be durable enough to withstand the elements over a long period of time so that the need for repairs is eliminated. To meet these demands, barriers are commonly constructed of concrete with internal steel frames for strength. Because these barriers are heavy and difficult to handle, it is efficient to build them at the location at which they are used rather than to manufacture them and subsequently place them at the construction site.
When building concrete barriers, two important considerations are that the barriers allow for proper drainage of water from the protected roadway, and that the barrier be sufficiently sectioned, with the sections spaced so as to allow for expansion and contraction of the concrete without their cracking due to changing atmospheric conditions. The present invention relates to an efficient and inexpensive method providing for these considerations.
Constructing barriers to discrete sections can be inefficient. The discrete sections must be individually placed and, as a result, may not, therefore, be perfectly aligned or separated. The operation of pouring concrete must be started and ended for each section, wasting time in starting and stopping, forcing longer use of the vehicle pouring the concrete and creating confusion as some workers are required to finish up a poured section, while other workers begin pouring concrete over the new section. Likewise, construction of the barriers as a single, unbroken unit is impractical with the prior art, due to the difficulty in cutting out proper spacing for drainage and expansion without prohibitive costs or damage to the cement matrix. The present invention provides for the pouring of a continuous barrier but eliminates the need for cutting thru the barrier subsequent to its completion. It also provides for precise placement of the spacing. The present invention saves time required by the construction of discrete sections and saves costs in labor and decreases interference with normal traffic use of the roadway being developed. Quick construction is an essential safety factor where the barriers are built on a right-of-way, to protect workers just off of the right-of-way. The present invention, which directs itself to the problem of proper separation of sections of such a concrete barrier, also provides a techniques for the quick and efficient construction of the barrier.
Various techniques have been developed for causing spaces to be formed in concrete for the purpose of for example allowing expansion due to changing atmospheric conditions or drainage or to form a hollow core. Spacing of concrete portions of roadbeds for allowing expansion of the section has been accomplished for example by inserting collapsable wedges into for example wet concrete. These wedges are then removed by removing an inner wedge and pulling the now loosened, outer wedge from the hardened concrete. See for example U.S. Pat. No. 3,052,945 (issued 9/11/62 to Cummings). U.S. Pat. Nos. 955,235 (issued 4/19/10 to Wellman), 3,677,688 (issued 6/18/72 to Morgan), and 3,694,531 (issued 9/26/72 to Glass) used collapsable cores set in wet concrete in order to form hollows in concrete blocks or wall structures. U.S. Pat. No. 1,120,534 (issued 12/18/14 to Rigby) used a similarly collapsable core to provide a mold for rope guides which is removed after hardening of the poured metal by collapsing the core. In each of these prior patents, the collapsable core is collapsed by removing a center part of the core or in U.S. Pat. No. 3,694,531 by using the action of a centrally located hydraulic jack to collapse the exterior, obliquely located sides of the collapsable core.
In U.S. Pat. No. 3,421,551 issued 1/14/69 to Currier) polystyrene expanded plastic foam or styrofoam was used in order to reserve spaces in poured concrete for pipe sleeves. This material was used because its high compressive strength allowed it to withstand the pressure of the poured concrete while being readily breakable or fungible so that it could be cut out. The high compressive strength as well as non-absorbent quality of styroform or other polyurethane or similar plastic material has also led to its use in forming molds for concrete construction in U.S. Pat. Nos. 3,350,049 (issued 10/31/67 to Reiland), 3,515,779 (issued 6/02/70 to Jones), and 3,689,021 (issued 9/05/72 to Liester). Reference is also had to the German Offenlegungsschrift No. 1,409,829 with an "anmeldetag" of 9/08/60.
The present invention envisions the use of a removeable core which utilizes an internal or inner core layer of a fungible material of high compressibility such as polystyrene expanded plastic foam in order to facililate collapsing and removal of the collapsable core. The core is used in order to provide the spacings between sections of concrete barriers whose construction is the object of the present invention.
The construction of concrete barriers reinforced with steel rods is well known in the art. Standard steel rods and machines for welding these together and for pouring concrete are available with existing materials and technology. Also in the existing art are torches, such as acetylene, for cutting or heating to shape the steel rods, as are arc and spot welding machines to connect or weld them together.
The general technique embodied in the present invention of generally building a metal latice and using this latice as a frame for supporting the poured concrete is also known in the art.
Various techniques have also been developed for holding acetylene torches and guiding them. See U.S. Pat. Nos. 988,950 to Rossell of Apr. 4, 1911; 2,170,305 to Inquersen of Aug. 22, 1939; 2,523,237 to Richardson of Sept. 19, 1950; 3,139,471 to Root of June 30, 1964; 2,596,133 to Donahue of May 13, 1952; 3,494,586 to Haynes of Feb. 10, 1970; 2,514,741 to Bullman of July 11, 1950; 895,026 to Jottrand and Lulli of Aug. 4, 1908; 1,553,508 to Cloud of Sept. 15, 1925; 2,291,199 to Anderson of July 28, 1942; and 3,350,540 to Andre of Oct. 31, 1967. The device for cutting metal at a fixed height of the barrier frame utilized in the present invention is generally considered only a secondary part of the invention as used in the present invention.
Concrete for cast-in-place barriers may be poured by machines well known in the prior art. These machines may be guided by electronically controlled aluminum arms which run along and are guided by a surface provided for this purpose. These arms are also known in the prior art.
In the past, concrete pouring machines have used strings tightly strung between rods placed in the earth as guides for pouring the concrete. The height of these strings is often inconvenient in that it interfers with workers operating on either side of the string. Additionally, it is often inconvenient to place rods in an unyielding or fragile surface, as when the concrete is being poured on a concrete slab as with the construction of bridge barriers. To remedy these problems, the present invention envisions the use of sections of pipe which plug together to form a continuous guide line along the ground. These pipes may be mounted on plates which are in turn mounted on bolts, so that the height at which they sit may be adjusted in order to be at the proper height to guide the pouring of concrete. These pipes may be so low along the ground that they do not impose much of a barrier to workers who pass on either side of the guide. Additionally, by sharpening the bolts on which these pipes ultimately rest, the guide becomes sufficiently secure along the ground so that it is unnecessary to drive rods into the ground, which is often unyielding concrete.
3. Summary Discussion of the Invention
The present invention provides a quick and efficient method for building barriers on-site with concrete.
It also provides for building a frame of steel rods which are evenly cut for the pouring of concrete.
It also provides a frame which contains properly located gaps into which removeable spacing sections or "cores" are inserted. When these cores are collapsed and removed after the concrete has been poured and allowed to set, these gaps provide spaces in an otherwise solid barrier for drainage of water and expansion of the concrete sections. These gaps are bounded by steel pins running laterally and parallel to the roadgrade. The rods may be capped with plastic tips, which may be attached to further ease the correct insertion and positioning of the "cores". The frame so designed is the major part of the invention. It provides that the spacing section may be placed in their respective locations in the frame quickly and immediately before concrete is to be poured, so as to prevent their being removed. Especially this prevents the cores from being thrown over the sides of bridges where the barriers are to be placed.
It provides for separating pieces which, when assembled, are of the same width as the gaps desired to be left within the concrete barriers. It also provides that these separating pieces have a central inner layer of fungible materials, which when cut out or hammered out will leave a space between the outer hard walls of the separating pieces into which space the outer pieces may be collapsed and subsequently removed, leaving a gap of the desired width behind.
This removeable, spacing core preferably includes a sandwich structure having an inner layer of fungible material (for example styrofoam or other plastic foam material) and outer, facing layers of hard material (for example "Masonite" and plywood or metal).
It also provides for x-bracing of the metal frames where the gaps are to be left in order to provide these points with additional strength and resilience as the end pieces of the respective sections of the barrier.
It also provides for a specially designed, positioning tool which may be used in order to assure that the gap left for the "cores" is at the correct angle to the road grade and that the gap be of the correct width and shape. This positioning tool is constructed in the form of a rectangular shaped box of the same width as the separating "core" pieces.
In the present invention, a matrix framework of steel bars is made by setting the steel bars into the bridge or roadside surface in concrete, and then connecting these bars thru welds to bars running laterally and perpendicularly to the bars set in the roadside. Likewise, the invention contemplates the use of steel rods and from the steel rods reinforcing a road or bridge bed to form the perpendicular part of the barrier frame. These bars may be properly shaped and aligned by using a prefabricated, wooden pre-frame in the shape of the metal, reinforcing frame to be built, where wooden x-members correspond in height and are located in just a position to where the metal rods are to be placed. This pre-frame may be of such design that the metal frame may be built within the wooden frame and after the metal frame is completed, the wooden frame may be lifted over the metal frame without requiring disassembly.
The present invention then provides that the metal bars perpendicular to the road surface be cut off at the same height from the road surface by means of an acetylene torch affixed at the desired height on a ringstand. The base of the ringstand rests on the surface and is perpendicular to the ringstand rod itself and parallel to the surface of the roadside or bridge on which it rests. The torch is held in place by holding members, such as screw clamps, which hold the blow torch tip to the rod of the ringstand. The entire arrangement may be quickly and easily moved from one steel rod to the next without detaching the blowtorch from the ring stand rod, so that the cutting process procedes with dispatch. It is desired that the steel rods all be at the same height so that the steel rods will not interfere with the pouring of concrete at a set and certain height and so that the mold on which the concrete is poured will be even.
The present invention also provides for a line of contact connectable pipe which rests on plates which in turn rest at an adjustable height on top of bolts. This line of pipe provides a guide for the concrete pouring machinery. Because the pipe rests on bolts, it is unnecessary to drive rods into the often unyielding surface below the guides in order to keep the guide in place at the proper height. Because the pipe is contact connected, it may be easily placed and removed. The bolts may have the ends which rest on the surface sharpened in order to make their contact with the surface more secure. This line of pipe may rest at a low height so as not to interfere with the movement of workers on either side of the guide.